This invention relates to systems and methods for processing and collecting blood, blood constituents, or other suspensions of cellular material.
Today people routinely separate whole blood, usually by centrifugation, into its various therapeutic components, such as red blood cells, platelets, and plasma.
Conventional blood processing methods use durable centrifuge equipment in association with single use, sterile processing systems, typically made of plastic. The operator loads the disposable systems upon the centrifuge before processing and removes them afterwards.
Conventional blood centrifuges are of a size that does not permit easy transport between collection sites. Furthermore, loading and unloading operations can sometimes be time consuming and tedious.
In addition, a need exists for further improved systems and methods for collecting blood components in a way that lends itself to use in high volume, on line blood collection environments, where higher yields of critically needed cellular blood components, like plasma, red blood cells, and platelets, can be realized in reasonable short processing times.
The operational and performance demands upon such fluid processing systems become more complex and sophisticated, even as the demand for smaller and more portable systems intensifies. The need therefore exists for automated blood processing controllers that can gather and generate more detailed information and control signals to aid the operator in maximizing processing and separation efficiencies.
The invention provides systems and methods for processing blood and blood constituents that lend themselves to portable, flexible processing platforms equipped with straightforward and accurate control functions.
More particularly, the invention provides systems and methods for processing blood using at least one fluid pressure activated pump and at least one fluid pressure activated valve. The systems and methods apply positive and negative fluid pressures to operate the pump and valve. Different pressure conditions are applied to the pump and the valve, to insure that a valve used in conjunction with a pump is not overcome by the pressure applied to operate the pump, and that both the valve and pump are not overcome by normal system processing pressures.
According to one aspect of the invention, the blood processing systems and methods make use of a cassette, which contains preformed, fluid pressure actuated pump stations, preformed fluid flow paths, and preformed, fluid pressure actuated valves in the fluid flow paths. The systems and methods also make use of a fluid pressure actuator to hold the cassette and selectively apply fluid pressure force conditions to the valves and pump stations in response to a control program. The systems and methods simultaneously place a first pump station in flow communication a blood separation device while simultaneously placing a second pump station in flow communication with a venipuncture. The fluid pressure actuator includes a manifold to apply a first fluid pressure force condition to the first pump station while applying a second fluid pressure force condition, different than the first fluid pressure force condition, to the second pump station. The differential pressures are applied because the first pump station is subject to and must overcome processing pressure conditions present in the blood separation device, whereas the second pump station is isolated from such processing pressures.
In one embodiment, the fluid pressure comprises positive and negative pneumatic pressure.
According to another aspect of the invention, the actuator holds the cassette and selectively applies fluid pressure force to the valves and pump stations to simultaneously place two pump stations in flow communication with the blood separation device, to supply and withdraw blood to and from the blood separation device, while simultaneously placing a third pump station in flow communication with a venipuncture, to supply and withdraw blood through the venipuncture. According to this aspect of the invention, the manifold applies a first fluid pressure force condition to the two pump stations while applying a second fluid pressure force condition, different than the first fluid pressure force condition, to the third pump station. Again, the differential pressures are applied because the first and second pump stations are subject to and must overcome processing pressure conditions present in the blood separation device, whereas the third pump station is isolated from such processing pressures.
In one embodiment, the fluid pressure comprises positive and negative pneumatic pressure.
According to another aspect of the invention, systems and methods process blood using a blood separation device that separates blood subject to a positive processing pressure. The systems and methods couple a fluid pressure actuated blood pump to the blood separation device and to a source of blood. The blood pump operates in response to an applied positive pump pressure to draw blood into the pump chamber and an applied negative pump pressure to expel blood from the pump chamber. The systems and methods govern communication between the source and the blood pump by a fluid pressure actuated inlet valve. The inlet valve operates in response to an applied positive valve pressure to close the inlet valve and an applied negative valve pressure to open the inlet valve. The systems and methods govern communication between the blood pump and the blood separation device by a fluid pressure actuated outlet valve. The outlet valve operates in response to an applied positive valve pressure to close the outlet valve and an applied negative valve pressure to open the outlet valve.
In one embodiment, the systems and methods operate the blood pump in a draw mode by applying a first negative valve pressure to the inlet valve while applying a second negative pump pressure to the blood pump and while applying first positive valve pressure to the outlet valve. The systems and methods control the absolute magnitudes of the pressures during the draw mode such that (i) the absolute magnitude of the first negative valve pressure is greater than the absolute magnitude of the second negative pump pressure and (ii) the absolute magnitude of the first positive valve pressure is greater than the absolute magnitude of the positive processing pressure. In this way, the magnitude of the positive valve pressure overcomes the positive processing pressure present in the blood separation device, to keep the outlet valve closed during the draw cycle. Furthermore, the magnitude of the negative valve pressure overcomes the magnitude of the negative pump pressure to keep the inlet valve open during the draw cycle.
In one embodiment, the systems and methods operate the blood pump in an expel mode by applying a first positive valve pressure to the inlet valve while applying a second positive pump pressure to the blood pump and while applying first negative valve pressure to the outlet valve. The systems and methods control absolute magnitudes of the pressures during the expel mode such that (i) the absolute magnitude of the second positive pump pressure is not greater than the absolute magnitude of the first positive valve pressure and (ii) the absolute magnitude of the first negative valve pressure is greater than the absolute magnitude of the positive processing pressure. In this way, the magnitude of the positive valve pressure overcomes the positive processing pressure present in the blood separation device, to keep the outlet valve open during the expel cycle. Furthermore, the magnitude of the positive valve pressure overcomes the magnitude of the positive pump pressure to keep the inlet valve closed during the expel cycle.
In one embodiment, the fluid pressure comprises positive and negative pneumatic pressure.